Extension device



Dec. 17, 1929.Y

E. F. M. sPElDx-:L ET AL 1,740,432

EXTENSION DEVICE Filed Aug. 25. 1928 -A TToRNEYS.

Patented Dec. 17, 1929 EDWIN F.

SAU.) AUGENSTEIN ASSIGF'OR T0 SD SPE'IDEL EXTENSION DEVICE Application filed August 23, 1928. Serial No. 301,683,

rthis invention relates to a foldable eXtension device 'for a Wrist Watch strap; and has tor its ob ject to provide latching means to securely hold the section; in folded position.

A iurther object ot the invention is the provision oit interconnecting parts carried by tivo 'toldable sections, the engaging surfaces of said parte being such that tension on one of the parts in a direction ot the extent of the strap when in working position will cause the interengaging parts to more securely prevent disconnection and unfolding ot' the sections.

The invention further consists in the torining 'troni an eye for engagement with the bail or lug oit a Wrist Watch a resilient tongue with e receive a pivot pin for hingedly contivo other sections together with the si tace oi the hool'; so positioned as to be inclined to the direction or' pull on the .strap and overlie the pivot pin sufficiently so tl it a 'pull in the direction of the strap wb in Working position will cause the pin to si ide further into the hook ra'her than snap troni engagement to permit un'i'olding of the sections.

lilith these and other objects in view, the invention consists of certain novel features of construction, will be more fully described, ani.l particularly pointed out in the appended claims.

in the accompanying drawings Figure l is a top plan view ot a wrist Watch with our extension devices attached to the baile or lugs thereof and With a portion of one ot the devices broken away to better show construction.

lligure 2 is a top plan view of the sections in extended position and partially broken away.

Figure 3 is a view similar to Figure 2 looking at the opposite or under side of the device.

Figure 4l is a central sectional view ot the device in extended position.

Figure 5 s a central sectional View ot the device in #folded position. n

liigure 6 is a sectional detail largely diagrannnatic showing the relation of the catch and latch parts of the device.

lt is found in the operation of extension de'i'fices ot the type shown in our co-pending application Serial No. 238,405, tiled December 7, 1927, that any unusual tension on a n ist Watch strap will cause the release of the means for holding the sections in folded position, and in order to provide a more secure clasp to hold the sections in folded position., we have formed latch and catch parts on tvvo it the sections with the engaging surfaces ot these parts such that any strain in the direction o1 the length of the strap Will cause 'the interengaging parts to niove further into engagement rather than to separate one from he other and more specilically we have ormed a hook to snap over and engage a 65 pir etal pin connecting two of the sections with the engaging surface of the hook inclined and overlying this pin so that any pull on the pin in direction of ext-ent of the strap, when in Working position, tends to slide the pin down the inclined surface of the hook into tui-ther interlocking engagement thereivith; and the following is a detailed description ot the present embodiment of this invention showing the preferred means by Which these advantageous results may be accomplished:

lVith reference to the drawings 10 designates the Wrist watch having lugs or barils 11 at either end thereof With the pins 12 of these bails removable for attaching or detaching thereto a device having an eye or loop to receive such a pin.

This extension device consists ot a section 13 of sheet stock rolled into an eye 1li at one end thereof through which the pin 12 extends to connect the extension device to the Watch. This eye is slit as at 15 to :torni a tongue 16 Which is reversely curved into a hook or latch part as illustrated at 17 in Figures 4, 5 and 6. n

Art the opposite end of the section 13 a pair of ears 27 are formed to pivotally receive trunnions 28 laterally extending` from an intermediate section 18 and to the opposite end of the intermediate section 18 there is hinged an end section 19 by means oit a pivot pin 20, the section 18 being cnt out as at 21 as to 'form a catch part to snap over the end 22 ofthe hook or latch part to securely fasten the sections in folded position.

The hook 17 is shown more or less diagrammatically in Figure 6 in which the arrow A denotes the direction of pull of the strap on the pivot pin or catch part 20 when the device is in folded position and the strap is in working position, from which it will be apparent that the `surface 23 of the hook 17 is inclined to the direction of pull A so that any strain on the strap will tend to cause the catch part to move down into the space 24 in the hook or latch thus moving these parts further into locking engagement.

1t will also be apparent from Figure 6 that, as the tongue 15 upon which the hook or latch is formed, extends a substantial distance throughout the length of theloop or eye 14 that a long resilient action of this latch part is obtained thus preventing` any leverage action on the hook part, tending to bend the end 22 of this hook from its position overlying the catch or pivot pin 20.

rihe strap 25 is suitably adjustably secured in the section 19 by means of a pin 2G adjustably positioned in openings 29.

The point of connecting being so placed as to be between the line of movement for disconnection of the pivot pin and hook and the section carrying the hook, whereby the normal strain of the strap is in the direction of the arrow A, Figure 6, as previously mentioned to cause the parts to move into locking engagement.

lThe foregoing description is directed solely towards the construction illustrated, but we desire it to be understood that we reserve the privilege of resorting to all the mechanical changes to which the device is susceptible, the invention being defined and limited only by the terms of the appended claims.

We claim 1. A foldable extension device for a wrist watch strap including two sections hinged together for folding one on the other, an enHV gaging member on one section in proximity to its free end having a recess facing said free end, a cooperating engaging member on the other of said sections in proximity to its free end for entering said recess, means to attach one of said sections to the bar of a wrist watch and strap end securing elements on the free end of the other of the sections in alignment with said engaging members when the members are in folded position whereby the. pull of the strap ends on the sections when folded are substantially in the plane of the engaging m-embers.

2. A foldable extension device for a wrist watch strap, including two sections hinged. ton

gether forifolding one on the other, a resililent hook-shaped engaging member on one section in proximity to its free end having a recess facing said free end, a cooperating engaging member on the other of said sections in proximity to its free end for engaging said recess, means for securing` the hook shaped member to a wrist watch and strap end securing elements on the free ends of the other of the sections in alignment with said engaging members when the members are in folded position whereby the pull of the strap ends on the sections when folded are substantially in the plane of the engaging members.

3. A foldable extension device for a wrist watch strap, comprising a. plurality of sec tions hinged together, one of said sections being formed into an eye for attachment to the lug of a wrist watch, a portion of said eye being extended to form a hook, and a catch part on anothei` of said sections to snap over said hook and hold said sections in folded position.

t. A foldable extension device for a wrist watch strap comprising three sections hinged together, one end section having its end formed into an eye to receive t-he bail of a wrist watch7 a portion of said eye being slit to form a resilient tongue reversely bent into a hoo-lr, a pivot pin connecting the other two sections and engageable with the hook to hold the sections in folded position, the engaging surface of said hook being inclined and overlying the said pin whereby a strain on the pin in the direction of the extent of the watch strap when in working position tends to pull the pin into further engagement with the hook. Y

5. A foldable extension device for a wrist watch strap-comprising three sections hinged together, one end section having its end formed into an eye'for attachment purposes, a portion carried by said eye carrying section bentinto a hoolr, a pivot pin connecting the other two sections and engageable with the hook to hold the sections in folded position, the engaging portion of said hook being inclined and overlying the said pin whereby a strain on the pin in the direction of the extent of the watch strap when in working position tends to pull the pin into further engagement with the hook. y

In testimony whereof we afiix our signatures.

EDWIN F. i/l. SPELDEL. KARL C. AUGENSTEHJ. 

